Eye replacement devices have been available for a number of years to effect functional and cosmetic improvements for the individual who has suffered the loss of an eye. Early ocular implants used in adults were spheres of glass or other inert solid material which filled the orbit, i.e., eye socket, and were then covered with a prosthesis which approximated the curvature and appearance of the human eye. The difficulty with these devices was that they could not be attached to the extraocular muscles. As a result, the prosthesis would not move with the functioning eye, and would both disconcert a person looking at the wearer and be a source of embarrassment to the wearer.
The devices were improved by providing means for attachment to the muscles in the orbit to permit movement in concert with the functioning eye and thereby approximate a more natural appearance. The procedure of attaching the implant device to the rectus muscles is complex but is nevertheless the most desirable procedure for an adult wearer of the implant device.
However, in the circumstance of a child born without an eye, or experiencing the loss of an eye, there is also the problem that the bone tissue surrounding the orbit increases in size as the child grows. An orbital implant which initially fits the child's orbit will soon become too small to stimulate further orbital growth, creating an unnatural appearance due to asymmetric bone growth and necessitating replacement of the ocular implant with a larger implant to stimulate similar bone growth around both orbits. If the implant device is attached to the eye muscles to mimic a natural appearance, a delicate operation must be performed to remove the implant device from the rectus muscles, followed by introduction of a new larger implant device which is reattached to those muscles. Depending on the child's age and stage of growth at the time of the first implant following enucleation, i.e., loss of the eye, the child may be required to undergo numerous additional operations to insert increasingly larger implants.